It's always a good idea to show both sides of a coin, but I'm fairly certain it's PMD. (post mint damage)
Hi, I have a few of those around here someplace. It is a Post Mint creation so it is not an error. I've seen this work so I know that the story is true but strange. Back in the day when pay phones were more common, A quarter altered that way could have a piece of thread tied around the deformed edge. The coin with the string could be dropped into a phone or vending machine just far enough to trigger the mechanism that would activate the phone or vending machine. The coin could then be pulled up and out of the slot that the coin was dropped into. It was a way to rip off phone companies and vending companies. I didn't believe it either until a guy in NY showed me how it worked. This guy had it down to such a science that the thread he dangled the coin on was knotted in such a way that the coin could only go into the phone so far. The length of the thread was different for the vending machines but the theory was the same. All that being said, I am pretty sure that that is what you have.
Great story foundinrolls! My dad worked with a con artist 20 or so years ago that figured out how to do the same thing with $20 bill and two pieces of tape. There's no telling how many times he ripped of the poker machine business.
